Because toluene is a solvent that is easily adsorbed on activated carbon and not soluble in water (see further discussion: Solvent regeneration with activated carbon: when to use steam and when inert gasses), the choice of recovery technology fell on adsorption with activated carbon and steam regeneration
THE RECOVERY OF SOLVENT MIXTURES: separating toluene by distillation
As anticipated in the previous section, the design of the plant took into account the client’s request to have a technology also suitable for the future recovery of a mixture of various solvents, potentially also soluble in water.
In order to ensure that recovery is still efficient , solutions were identified, some of which were installed in the first phase, and others to be installed in the future
Installations planned in the first phase:
- The main components of the plant were made of materials compatible with contact with solvent mixtures.
- The main components of the plant have been oversized for use under more severe conditions resulting from the presence of solvent mixtures
In the eventual second phase, the facility may be implemented with additional modifications:
- Increasing the amount of activated carbon
- Installation of a distillation unit that allows separation of toluene from other solvents according to the composition required by the customer, to enable maximization of reuse
Toulene solvent: the achievements of the recovery plant.
The plant met all the requirements that the customer had set as fundamental, including compliance with the strictest environmental regulations and the recovery and reuse of toluene with a degree of purity comparable to the product that can be purchased on the market.
The operating costs proved to be highly sustainable, confirming the customer’s expectation that the investment would pay for itself in a short time, so the recovery solution was preferred over the purchase solution.
The technical solution identified is also in perfect harmony with the philosophy of the client, which promotes the use of advanced ecological solutions that are also ecologically sustainable and oriented towards “clean” industrial production models that favor the reuse of the products and also have a lower CO2 impact.